alt Hacker NewsRead some mature Discworld content (Guards! Guards! is the best entry point, I'd say), it's an easy read too. Pratchett's skill with English would make even a tax report smooth and riveting.
No need to always flex with some highbrow stuff to find a masterful style.
Yes - he's popular for a reason, not pop, but that he deserves popularity. I wonder about being highbrow... in that yes you're right, that's how he's viewed, and he's well-known and it's fantasy and it's comedic and therefore cannot be highbrow (awful how we judge these things) but he has some very insightful ideas or ethics he wants to communicate. If, to me, lowbrow vs highbrow is about depth or insight, or long-lasting value in literature (will he be read in a hundred years? Yes), he is high, even if 'easy'. You're absolutely right, 'masterful' in style.
He writes sentences around how they're, eh, delivered? Can't think of a better word. Lots of footnotes and clauses and parentheticals. And the timing of his words make the jokes.